Machine for producing gears



Nov. 26, 1940. w. FORSTER MACH INE FOR PRODUCING GEARS Filed Jan. 7, 1959 2 Sheets-Sheet l ll) vemor W. R rsfe 7* Nov. 26, 1 940.

W. FORSTER MACHINE FOR PRODUCING GEARS 2 Sheets-Sheet 2 Filed Jan. 7, 1959 lnvemar W Forster Azlorne y Patented Nov. 26, 1940 2,222,7(1t MACHINE or. PRODUCING GEARS Werner Forster, Zurich, Switzerland, assignor to Maagszahnrttder und-Mas chinenfA; g zurich,

Switzerland p at nu '7 1939., steam 2 93. 8 I In Germany nuarrt 193.8

Claims. (01. 90'

This invention relates to a machine for producing gears on the rolling principle of the type disclosed in the resissued patent to Marry; No. 14,908 or in the German Patent No.. 395,662.

6 This machine includes a rotary controller which performs one complete revolution during a cycle of operation of the machine and governs the functions of the machine. The machine is equipped with a shaping tool of rack form. The controlling mechanism of the machine ordinarily functions to cause the machine at any cycle of operation to work in one tooth space of the blank only. The blank performs a rolling motion extending over one tooth space at any cycle. If it is desired to extend the rolling motion within a cycle over two or more tooth spaces in order to have the rack-shaped tool work with a larger section of its length in favor of a more uniform wear, special gear transmissions must be provided. This operation results in a gain of time since the operation required after any indexing motion for taking up the lost motion of the rolling elements need be performed once only for a plurality of teeth. These advantages, 25 however, are connected with a disadvantage. If

the rolling motion in a cycle of operation is to be extended .over a plurality of tooth spaces without increasing the rolling speed, it is necessary that the speed at which the rolling members are driven be reduced.

An object of the present invention is to avoid these disadvantages. According to a feature of the invention, atimed mechanism is coordinated to the meansdriving the rotary controller and is adapted to temporarily disable these driving means in order to arrest the rotary controller during any cycle of operation for a certain. period of time. The machine is thus caused during this period of time .to continue the operation which it performed at the instant atwhich the controller was arrested. In this manner, it is possible to extend the rolling operation over any desired. number of .tooth'spaces within a cycle and to cut the teeth therein without varying the normal speed of the controlling operations.

The drawings illustrate two embodiments .of a machine for cutting spur gears.

Fig. 1 is an elevation of a gear shaping machine embodying the, invention, partly shown in section;

Fig. 2 is a plan view of the work table, the gearing being diagrammatieally indicated;

Fig. 3 is an elevation of the timed mechanism i Fig. 4 shows an elevation of a gear grinding m Qhi e$imi1art9i s-,1.a d

Fig.5 is a 'agrarnmatic representation of the ion o t e ork d du a cle of operation.

The fram I n th hi i isms vided with horizontal guide ways on which a Q; slide 2 is movable. -On this slide there is mounted a tary. ab ca ble o turning ab a vertical axis. table carries the blank 4 h ch i rigidl onne d the e i in axia registry. Jocoinmr 1 ef the frame 1 is provided 1!]. with vertical guide ways on which a reciprocatory ram 5 is movable carrying the rack-shaped tool 6. .The ram is moved up and down through a crank mechanism comprising a crank shaft 9,

a crank disc 8' and a connection rod 1. The'shaft 15' 9 is driven from a motor through a clutch (not shown) and a pair of gears H], II. From the crank shaft 9 (Fig. 2) an auxiliary drive is derived through a pair of bevel gears l2, I3 serving the purpose of performing the rolling mo- 26 tion. The bevel gear [3 is connected with a shaft [4 diagrammatically indicated in Fig. 2 and the shaft l4 carries a crank mechanism l5, i5a of adjustable stroke including a connection rod l6 adapted to reciprocate a ratchet pawl N3 25 (Fig. 1) engaging a ratchet wheel ll.

In lieu .of the ratchet pawl other suitable elements 18a. acting in one Way only may be employed. In this manner,- a shaft I!) connected with the .ratchet wheel I! is intermittently 30 driven. This motion is transmitted from the shaft I9 through a pair of meshing gears 20 and 2| to an auxiliary shaft 22. This shaft may be driven in the opposite direction by auxiliary means to be described later. It operates a pair 35 of gears .23, 24. A The hub ,of the gear .24 is loosely mounted on a shaft. 25and is constructed as a double clutch 26, 26a, each end of this clutch being adapted to engage a member 21, or 21a respectively, which. is slidably mounted on the 40 shaft 25 but secured against relative rotation thereto. The teeth of these clutches are facing in opposite directions, whereby the shaft 25 may be driven in either directionof rotation of the gear 24. By means of these clutch members, the 45 shaft 25 may be stopped in one direction of rotation, forinstance, at the beginning and at the termination of the operation on a blank, by disengagement of these clutches through manual operation of an actuating lever 25.

By means of gear transmissions 29, v30, or 3|, 32, 33 respectively, the rotation of the shaft 25 is transferred to a gear shaft 34 and thence through a further pair of. gears .35, 36, to the rotary controller formed by a cam drum 31, 55

through a pair of clutch members 65.

Two clutch members 38 and 39 having teeth of opposite direction are interposed between the shaft 25 and the two gears 29 and 3| loosely mounted thereon. The teeth of the clutch members 38 and 39 engage complementary teeth provided on the hubs of the gears 29, 3|. Depending on the rotation of the shaft 25 one of these gears is driven while the clutch of the other gear slips.

The motion of the shaft 22 is transferred through a pair of bevel gears 4|], 4| and the table shaft 42 to a pair of bevel gears 43, 50. From this pair of bevel gears, the rolling motion of the machine is derived. For this purpose, the slide 2 mounted on straight horizontal guide ways has a nut 45 attached to it engaging a screw spindle 44 which is rotatably mounted and secured against longitudinal displacement. The rotary work table 3 mounted on the slide 2 has a worm wheel 46 attached to it engaging a worm 41 adapted to impart a rotary motion to the work table. The displacement of the slide 2 and the rotation of the work table are so proportioned that the blank performs a rolling motion relative to the rack-shaped tool. H I

Two groups of change gears 48 and 49 connect the spindle 44 and the shaft of theworm 41 with the bevel gears 43, 50. The change gears 48 and 49 are selected to meet the requirements depending on the number of teeth and the pitch of the gear to be cut. 7

When the slide 2 arrives at the end of its rolling stroke, the reciprocatory motion of the toolcarrying ram 5 is interrupted and the slide 2 together with the work table 3 and the blank 4 is returned moving backwards the entire rolling stroke along a straight line, while the rotary motion of the table 3 is interrupted. The ram 5 is stopped by action of a cam 5| of the controller drum 37, the cam acting through a follower 52 and a lever 53 on a link 54 disengaging a clutch (not shown) interposed between the driving motor and the crank shaft 9. Thereupon another cam 55 of the controller actuates a follower 56, thereby putting an auxiliary driving mechanism for shaft 22 in operation. This auxiliary driving mechanism comprises a clutch member 51 mounted on the shaft 22 for common rotation therewith and longitudinal displacement thereon and adapted to engage a clutch member 51b, at the same time disengaging a clutch member 51a. On the clutch member 5'") there is provided a gear 58 meshing with another gear 59. The clutch member 511) is freely rotatable on the auxiliary shaft 22, whereas the gear 59 is fast on a shaft 60 of a pulley 6| continuously driven by the driving motor of the machine.

When the crank shaft 9 was stopped by action of the controller 31, the intermittent actuation of the shaft I9 ceased. The direction of rotation of the shaft 60 is such that upon engagement of the clutch members 51 and 512) the auxiliary shaft 22 is driven from the shaft 6|] in the opposite sense. This has the effect of driving shaft 42 and the pair of bevel gears 43, 5|] in the opposite direction whereby the movement of the slide 2is reversed. Similarly, the rotary motion of the table 3 being effected through the change gear 49, an auxiliary shaft 66 and a pair of gears 51 68 from the pair. of bevel gears 43, 50 is likewise reversed. The gear 6'! is freely rotatably mounted on the shaft 66 and is adapted to be connected therewith for common rotation Upon reversal of the gears 43, 50 the rolling motion of the blank is reversed by the simultaneous motion of the slide 2 and the table 3 in reversed direction over a short distance. Then, a cam 62 of the controller 31 arrives in position to act on a follower 63 disengaging the clutch 55 through a linkage 64, whereby the rotary motion of the table 3 is interrupted while the slide 2 continues its translatory movement. Therefore, the table 3 continues its return movement without any rolling motion thus indexing the blank in a known manner. Then, the cam 55d of the controller arrives in position to act on the follower 55 thereby re-engaging the clutch 5?, 5 5a and thus terminating the return movement of the blank. A short rolling motion in working direction serving the purpose of taking up any lost motion while the tool is still at rest, is subsequently effected by the action of a cam 83 of the controller 37. This cam actuates a follower 84 mounted on a lever 85 shifting a clutch member 88 which is keyed to a shaft 81 for common rotation therewith. This shaft is continuously driven from the shaft 60 through the gear 59 and a gear 86 meshing therewith. The clutch member 88 is shifted into engagement with a clutch 89 integral with a gear 90 loosely mounted on shaft 8'! and meshing with a gear 9! which is integral with the gear 2| and the clutch member 51a. Therefore, the engagement of the clutch members 88 and 89 causes the shaft 22 to be driven at a reduced speed in the positive rolling direction, whereby the rolling motion is initiated at a reduced speed to take up any lost motion.

A feature of the present invention resides in the provision of means for temporarily stopping the controller 31, if it is desired, to extend the rolling motion within the cycle of operation over n tooth spaces. The period of time during which the controller is thus, stopped may be chosen as required by the length of the rolling motion. When the rolling motion shall be ex-- tended over n tooth spaces, the controller is stopped for n-l tooth spaces.

To this end, the two clutch members 38 and 39 on the shaft 25 are disengaged at a predetermined instant. ,For this pur-p0se, each clutch memb is provided with an annular groove engaged by studs 69 carried by a bifurcated lever 10 provided with a follower H. The two followers 1| engage cam faces of a rotatable cam plate 12. This cam plate is pivotally mounted and may be rocked through a link 13 carrying a follower l4. follower is operable by a timed mechanism. timed mechanism is in permanent driving connection with the shaft 25. For this purpose, thi shaft is geared with a worm 11 through a pairof bevel gears 15, 16. The worm engages a worm wheel 18 attached to a shaft '19. On this shaft 19 there is firmly mounted a disc 80 shown Figs. 2 and 3 which constitutes the timed mechanism. The disc is provided with a plurality of. circumferentially distributed holes marked b suitable numbers as shown in Fig. 3. Stops 8| and 8 la may be selectively inserted in these holes. These stops are formed with cam grooves 32 and 82a which are inclined relative to the plane of the disc 8!]. Upon rotation of the disc the grooves 32 and 8211 are adapted to engage over the follower 14 thus longitudinally shifting the link 13, The shaft 25 and the disc 80 geared thereto rotate alternately in opposite directions. Depending on their setting on the disc, the stops 8|, 81 a, engage the follower 14 at different times to engage and disengage the clutch members 38 and 39. In this manner, the controller 31 may be temporarily stopped during the cycle of operation at various instants and for diiIerent periods of time.

The operation is as'follows: When the machine is set up for an operation in which a single tooth space only is worked upon at any cycle, the cycle is comprised of the following operations diagrammatically indicated in Fig. 5:

I. The controller :31 is intermittently rotated step by step through revolution whilethe blank is rolled forward by action of the crank shaft 9 operating the ratchet mechanism I5, l6, H. During this operation the reciprocatory shaping tool works on' the blank within a single tooth space, while the cam 5| remains in engagement with the follower 52. Upon completion of this partial revolution of the controller the cam 5| disengages the follower 52 thus stopping the crank shaft 9 and arresting the tool. Immediately afterwards the cam engages the follower 56 shifting the same towards the right thus disengaging the clutch member 5'! from the clutch member 51a and engaging it with the clutch member 51b, whereby the rotation of shaft 22 is reversed.

II. During the following & revolution of the controller the blank is rolled backwards. Then, the cam 62 arrives in engagement with the follower 63 moving the same towards the right, whereby the clutch 65 is disengaged terminating the rotation of the work table 3.

III. During the following revolution of the controller the blank performs a translatory return motion by movement of the slide 2 without rotation of the table 3. At the end of this step the cam 62 disengages the follower 63 thus reengaging the cam. 65.

IV. During the following revolution of the controller the blank performs a return rolling motion. At the end of this step the cam 55a engages the follower 56 rocking it towards the left thus disengaging the clutch member 51 from the clutch member 51b and re-engaging it with the clutch member 51a. At the same time the cam 83 engages the follower 84, whereby the clutch members 88 and 89 are engaged. This has the effect of reversing shaft 22.

V. During the subsequent revolution of the controller the blank is rolled forward. At the end of this step the cam 83 disengages the clutch members 88 and 89; at the same time, the cam 5| causes the driving clutch of the cam shaft 9 to be re-engaged, whereby shaft 22 will be driven at normal speed thus resuming the intermittent rolling motion and the cutting operation of the step No. I. The cycle of operation is now completed.

If it is desired to set up the machine for a rolling motion in which a larger number of tooth spaces are worked upon within a single cycle, for instance, nine tooth spaces, I provide means for temporarily stopping the controller in the position A (Fig. 5) during the step I shortly after the commencement thereof. For this purpose,

' the stops 8|, 8la on the disc 80 are inserted in holes which are nine units apart. When the point A is reached in the performance of period I of the cycle, the stop 8| engages the follower 14 thus causing the cam plate 12 to be rocked in clockwise direction thereby disengaging the clutch members 38 and 39. Consequently, the controller 31 stops while the rolling motion derived from shaft 22 is continued. After eight tooth spaces have been worked upon by the tool at normal speed, the stop 8la on the disc 8|] arrives in engagement with the follower 1.4 and shifts the link 13 thus re-engaging the clutch members 38 and 39. Consequently, the controller resumes its rotary motion controlling the subsequent operations as above described.

Early in the period 111 of the cycle at the instant A1 (Fig. 5) the stop 8| provided with the cam groove 82 has returned to engagement with the follower l4 disengaging the'clutch members 38, 39 and stopping the controller. While the controller is at rest, the return motion ofthe slide 2 continues through eight tooth spaces and the disc 80 keeps on to turn until the stop 8la engages the follower l4 and thus re-engages the clutch members 38 and 39 putting the controller 31 in operation. After the slide 2 has moved the remaining ninth tooth space, the controller 3! acts on the mechanisms above described to continue the cycle of operation through the periods IV and V as above described, whereupon the new cycle of operation commences.

In the embodiment above described the tool is formed by a rack-shaped planing tool. However, a shaping tool in form of a single tooth may be used for cutting large gears. In this event, a very extended rolling motion is required. More-.- over, I may substitute two dished grinding discs Ba for the rack-shaped tool, these discs being driven by two motors 8b as shown in Fig. 4. These grinding discs work in the same manner as a shaping tool formed with a single tooth. In these events, it is particularly desired to temporarily arrest the controller during the extended rolling motion or return motion. This has the advan-' tage that the rolling motion and the return mo.- tion of the blank may be extended without modifying the speed of the rolling motion of the blank and of the' operation for taking up the lost motion. Therefore, these operations may be performed at the ordinary speed.

,With the use of a tool formed with a single tooth or of grinding discs as described, the operation differs from that above described in that the indexing motion is to be limited to a single tooth space. The rolling motion and the return motion, however, extend over a plurality of tooth spaces, for instance, nine tooth spaces per cycle. The limited indexing motion requires that on the return stroke the rotation of the table 3 isinterrupted for a single tooth space only. For this purpose, the disc 80 (Fig. 2) is angularly displaced on its shaft l9 through a predetermined small angle and attached to the shaft 19 in its new position. This has the effect that the clutch members 38 and 39 are disengaged by the stop BI at the instant B1 of the period II of the cycle of operation (Fig. 5). Hence, the controller remains at rest during the return rolling motion extending through eight tooth spaces while the control disc turns through the angular distance of the stops BI and am, whereupon the operation is terminated in normal manner indexing the blank one tooth space. In the period I of the cycle the corresponding stoppage of the drum commences at the instant B.

The timed mechanism for arresting the controller may be also used in cutting gears having a small number of teeth and a large pitch. In work of this type the machines used prior to my invention have an extremely fast rolling motion.

In order to avoid this disadvantage, the stops 8|,

8la may be inserted in the holes 'I and 9 of the r of the normal speed, whereby the rolling motion is slowed down as desired.

While I have described my invention by reference to a specific embodiment thereof, I wish it to be understood that it is not limited to the details thereof but is capable of numerous modifications which will readily occur to anyone skilled in the art. This applies particularly to the specific design of the timed mechanism for temporarily stopping the controller.

What I claim is:

1. A machine for producing gears operating on the rolling principle, comprising a rack-shaped tool, a Work carrier, a mechanism causing said Work carrier and said tool to perform, within a Cycle, a relative rolling motion, a return motion and an indexing motion, a rotary controller governing the operation of the machine being adapted to perform one complete revolution during a cycle of operation, means driving said controller, and a timed mechanism coordinated to said driving means and adapted to temporarily stop said controller in any cycle of operation thus causing the machine during the temporary stoppage of said controller to continue the operation performed by the machine at the instant of the interruption of the revolution of said controller.

2. A machine for producing gears operating on the rolling principl comprising a rack-shaped tool, a work carrier, a mechanism causing said work carrier and said tool to perform, within a cycle, a relative rolling motion, a return motion and an indexing motion, a rotary controller governing the operation of the machine being adapted to perform one complete revolution during a cycle of operation, means driving said controller, and an adjustable timed mechanism coordinated to said driving means and adapted to temporarily stop said controller for a variable period of time in any cycle during said rolling motion thus enabling the machine during the temporary stoppage of said controller to continue said rolling motion for a period of time variable by adjustment of said timed mechanism.

3. A machine for producing gears operating on the rolling principle comprising a rack-shaped tool, a work carrier, a mechanism causing said work carrier and said tool to perform, within a cycle, a relative rolling motion, a return motion and an indexing motion, a rotary controller governing the operation of the machine being adapted to perform one complete revolution during a cycle of operation, means driving said controller, a timed mechanism coordinated to said driving means and adapted to temporarily stop said controller in any cycle thus enabling the machine during the temporary stoppage of said controller to continue the operation performed by the machine at the instant of the interruption of the revolution of said controller, and adjustable means for variably determining said instant.

4. A machine for producing gears operating on the rolling principle, comprising a rack-shaped tool, a work carrier, a mechanism causing said work carrier and said tool to perform, within a cycle, a relative rolling motion, a return motion and an indexing motion, a rotary controller governing the operation of the machine being adapted to perform one complete revolution during a cycle of operation, meansdriving said controller including a clutch, a rotary support, means for rotating said support, and adjustable abutments on said support adapted to disengage and engage said clutch to temporarily stop said controller in any cycle of operation thus causing the machine during the temporary stoppage of said controller to continue the operation performed by the machine at the instant of the in terruption of the revolution of said controller.

5. A machine for producing gears operating on the rolling principle, comprising a rack-shaped tool, a work carrier, a mechanism causing said work carrier and said tool to perform, within a cycle, a relative rolling motion, a return motion and an indexing motion, a rotary controller governing the operation of the machine being adapted to perform one complete revolution dur ing a cycle of operation, means driving said controller including a clutch, a rotating shaft, a support mounted on said shaft, and adjustable abutments on said support adapted to disengage and engage said clutch to temporarily stop said controller in any cycle of operation thus causing the machine during the temporary stoppage of said controller to continue the operation performed by the machine at the instant of the disengagement of said clutch, said support being angularly adjustably fixed to said shaft to variably determine the instant of disengagement of said clutch.

WERNER FORSTER. 

